title: Comparison between the deconvolution and maximum slope 64-MDCT perfusion analysis of the esophageal cancer: is conversion possible?
abstract: OBJECTIVE
  To estimate if CT perfusion parameter values of the esophageal cancer, which were obtained with the deconvolution-based software and maximum slope algorithm are in agreement, or at least interchangeable.
  
  
  METHODS
  278 esophageal tumor ROIs, derived from 35 CT perfusion studies that were performed with a 64-MDCT, were analyzed. "Slice-by-slice" and average "whole-covered-tumor-volume" analysis was performed. Tumor blood flow and blood volume were manually calculated from the arterial tumor-time-density graphs, according to the maximum slope methodology (BF(ms) and BV(ms)), and compared with the corresponding perfusion values, which were automatically computed by commercial deconvolution-based software (BF(deconvolution) and BV(deconvolution)), for the same tumor ROIs. Statistical analysis was performed using Wilcoxon matched-pairs test, paired-samples t-test, Spearman and Pearson correlation coefficients, and Bland-Altman agreement plots.
  
  
  RESULTS
  BF(deconvolution) (median: 74.75 ml/min/100g, range, 18.00-230.5) significantly exceeded the BF(ms) (25.39 ml/min/100g, range, 7.13-96.41) (Z=-14.390, p<0.001), while BV(deconvolution) (median: 5.70 ml/100g, range: 2.10-15.90) descended the BV(ms) (9.37 ml/100g, range: 3.44-19.40) (Z=-13.868, p<0.001). Both pairs of perfusion measurements significantly correlated with each other: BF(deconvolution), versus BF(ms) (rS=0.585, p<0.001), and BV(deconvolution), versus BV(ms) (rS=0.602, p<0.001). Geometric mean BF(deconvolution)/BF(ms) ratio was 2.8 (range, 1.1-6.8), while geometric mean BV(deconvolution)/BV(ms) ratio was 0.6 (range, 0.3-1.1), within 95% limits of agreement.
  
  
  CONCLUSIONS
  Significantly different CT perfusion values of the esophageal cancer blood flow and blood volume were obtained by deconvolution-based and maximum slope-based algorithms, although they correlated significantly with each other. Two perfusion-measuring algorithms are not interchangeable because too wide ranges of the conversion factors were found.
authors.affiliation: Unit of Digestive Radiology (First Surgical Clinic), Center of Radiology and MR, Clinical Center of Serbia, Belgrade, Serbia. avstefan@eunet.rs
authors.forename: A
authors.initials: A
authors.lastname: Djuric-Stefanovic
authors.forename: Dj
authors.initials: Dj
authors.lastname: Saranovic
authors.forename: D
authors.initials: D
authors.lastname: Masulovic
authors.forename: A
authors.initials: A
authors.lastname: Ivanovic
authors.forename: P
authors.initials: P
authors.lastname: Pesko
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D004938:Esophageal Neoplasms / Q000150:complications* / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods*; D009389:Neovascularization, Pathologic / Q000150:complications* / Q000000981:diagnostic imaging*; D055420:Perfusion Imaging / Q000379:methods*; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: CT perfusion; Deconvolution; Esophageal cancer; Maximum slope; Multi-detector computed tomography